Raspberry pi to sense voltages 12 to 24, what buffer is good?

Question

Hello I’m looking to use my raspberry pi in an automotive application where it will be used to detect when the vehicles ignition is activated and de activated. I would like the system to be 24 volt tolerant just to maintain application flexibility. I was thinking something like a buffer which would translate input voltages 12 to 24 to 3.3v logic for the raspberry Pi to detect. What’s the most suitable hardware or circuit to use? Regards

Unclear whether this is for an analog input or digital input. What signal do you look at to detect ignition? — DKNguyen, May 14 '20 at 18:37

score 0 · Answer 1 · answered May 14 '20 at 18:37

0

Resistor divider with a diode clamp.

schematic

^{simulate this circuit – Schematic created using CircuitLab}

answered May 14 '20 at 18:37

DKNguyen

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How will this be with constant 24 volts? Thanks – Seeedawg May 14 '20 at 19:58
It won't be. This just scales down any signal between 0 and 24V to a range between 0 and 3.3V. Your clarification for a constant 24V signal does not make sense because a constant signal carries no information and is useless. – DKNguyen May 14 '20 at 20:11

Raspberry pi to sense voltages 12 to 24, what buffer is good?

1 Answers1